No, she is only infectious from the site of her infection - her mouth.
Have you ever tested for hsv1? Over half of adults in the US, and 2/3 globally, have hsv1, and you could have it and not know it. 90% of those who have never get symptoms. If you have it, you can't get it again.
Ask your doctor for a type specific IgG test. It's not easy to get in the UK, so you might have to tell your doctor that you had a sore on your mouth that you think is herpes.